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56 terms

Chapter 13- Minerals

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Mineral
any naturally occurring inorganic solid that possesses an orderly crystalline structure and a well-defined chemical composition
Amorphous
without form [referred to when speaking about things with a lack of atomic structure]
Rock
any solid mass of mineral or mineral-like matter that occurs naturally as part of our planet
Element
a substance that cannot be broken down into simpler substances by chemical or physical means
Chemical compounds
when elements are reactive and join together with atoms of one or more other elements [most minerals are chemical compounds consisting of two or more different elements]
Nucleus
central region of an atom
Protons
very dense particles with positive electrical charges
Neutrons
have the same mass as a proton but lack an electrical charge
Electrons
contain negative electrical charges
Principal shells/energy levels
regions in which individual electrons move around the nucleus
Valence electrons
electrons in the outer most principal shell/energy level [a valence shell has a stable configuration when it contains eight electrons]
Chemical bond
sharing or transferring of electrons to attain a stable electron configuration among bonding atoms
Ionic bond
when electrons are transferred
Covalent bond
electrons are shared
Ionic compounds
consist of an orderly arrangement of oppositely charged ions assembled in a definite ratio that provides overall electrical neutrality
Mass number
the total number of its neutrons and protons [elements will always have the same number of protons, but the number of neutrons may differ in certain atoms of the same element]
Isotopes
atoms with the same number of protons but different numbers of neutrons [isotopes are indentified by placing the mass number of an element after its name]
Radioactive decay
when isotopes disintegrate and emit particles [discussed more in depth in chapter 11]
Luster
the appearance or quality of light reflected from the surface of a mineral [examples of luster: metallic (having the appearance of metals regardless of color), submetallic (basically metallic but with some dull coating or tarnish b/c of exposure to the atmosphere), or nonmetallic (which include- vitreous, glassy, dull, earthy, pearly, silky, or greasy)]
Ability to transmit light
this is (obviously...) a mineral's ability to transmit light, there are three words for this [opaque- no light is transmitted, translucent- when light but not an image is transmitted, transparent- when light and an image are visible]
Color
most conspicuous characteristic, but only used to indentify a few minerals [that is because slight impurities can cause a color change, which makes it ambiguous or even misleading]
Streak
the color of the powdered mineral- obtain obtained by rubbing a mineral across a streak plate [can distinguish metallic from nonmetallic b/c metallic minerals usually have a dense, dark streak, while nonmetallics usually have a light colored streak]
Crystal shape or habit
the common or characteristic shape of a crystal or aggregate of crystals [ex.- pyrite] terms used to describe crystal habits are equant, bladed, fibrous, tabular, prismatic, platy, blocky, or botryoidal
Mineral strength
how easily minerals break or deform under stress relates to the type and strength of the chemical bonds that hold the crystals together [next four words are used to describe mineral strength]
Tenacity
a mineral's toughness or resistance to breaking or deforming [minerals can be brittle (shatter into small pieces when struck), malleable (easily hammered into different shapes), sectile (can be cut into thin shavings), or elastic (will bend and snap back to their original shape after the stress is released)]
Hardness
extremely useful diagnostic property, measure of the resistance of a mineral to abrasion or scratching [measured by the Mohs scale of hardness, which consists of 10 minerals arranged in order from 1 to 10]
Mohs scale of hardness (really important to know b/c canavan always refers to it on tests and stuff)
relative scale of ranking hardness of minerals [scale of index minerals is 1. Talc 2. Gypsum 3. Calcite 4. Fluorite 5. Apatite. 6. Orthoclase 7. Quartz 8. Topaz 9. Corundum 10. Diamond and scale of common objects is 2.5 finger nail 3.5 copper penny 4.5 wire nail 5.5 glass and knife blade 6.5 streak plate]
Cleavage
the tendency of a mineral to break (cleave) along planes of weak bonding [note: not all minerals have cleavage, but those who do can be indentified by the relatively smooth, flat surfaces that are produced when the mineral is broken] do not mix up cleavage with crystal structure
Fracture
minerals having bonds that are equally, or near equally, strong in all directions (do not break off in any sort of patterned way)
Density
mass per unit volume (usually expressed as grams per cubic centimeter)
Specific gravity
a unitless number representing the ratio of a mineral's weight to the weight of an equal volume of water [most rock-forming minerals have a S.G. of 2 to 3, but denser minerals (like pyrite or gold) have a higher S.G.]
Hydrochloric acid test
a drop of this will make the mineral group carbonates fizz (most useful for identifying calcite)
Talc
feels soapy
Graphite
feels greasy
Sulfur
smells like rotten eggs
Magnetite
can be picked up by a large magnet and makes compasses spin uncontrollably
Silicon and oxygen
two most abundant minerals in Earth's crust, when they combine, they create the framework for the most common mineral group- the silicates
The silicates
account for more than 90 percent of the Earth's crust, are made up of silicon and oxygen
Silicate mineral
each silicate mineral contains oxygen and silicon atoms, and most (except for quartz and a couple others) contain one or more additional element in their crystalline structure. General formula: metal + Si + O (in varying proportions) ex. Hornblende, Ca2(Fe,Mg)5Si8O22
Silicon-oxygen tetrahedron
fundamental building block of all silicates [consists of four oxygen atoms surrounding a much smaller silicon atom] and in each hand sized silicate mineral there are millions of these
Primary elements that join silicate structures
iron, magnesium, potassium, sodium, and calcium
Feldspar
most plentiful mineral in Earth's crust (around over 50% of the Earth's crust)
Quartz
second most abundant mineral in the crust, only common mineral made solely of silicon and oxygen
Silicate structure
internal structure of the mineral [relationship exists between this and the cleavage a mineral exhibits]
Nonsilicates
mineral group that is far less abundant in Earth's crust than the silicates (next couple of points are all different nonsilicate groups)
Carbonates
characterized by the carbonate ion (CO3) and one or more kinds of positive ions. General formula: metal + CO3 ex. Dolomite, CaMg(CO3)2 [most common carbonate- calcite]
Oxides
characterized by the presence of one or more metals and oxygen. General formula: metal + O (in varying proportions) ex. Corundum, Al2O3
Sulfides
characterized by the presence of one or more metals and sulfur. General formula: metal + S (in varying proportions) ex. Galena, PbS
Halides
characterized by the presence of one or more metals and a halogen (second column from right in periodic table). General formula: metal + halogen (in varying proportions) ex. Halite, NaCl
Sulfates
characterized by the presence of the sulfate ion (SO4) along with one or more metals. General formula: metal + SO4 (in varying proportions) ex. Barite, BaSO4
Native elements
characterized by the presence of a single element ex. Sulfur, S
Mineral resources
Earth's storehouse of useful minerals that can be recovered for use
Reserves
deposits from which minerals can be extracted profitably
Ore
a useful metallic mineral that can be mined at a profit (can be applied to some nonmetallic minerals, such as fluorite and sulfur)
Industrial rocks and minerals
like ores, except can be used for purposes like building stone, road paving, abrasives, ceramics, and fertilizers
Gemstones
precious have beauty, durability, and rarity and semi-precious only have one or two of the precious qualities (box on p 46 has all precious and semi-precious gems listed)